Corrugated drainage pipe with staggered arrangement of plateau recesses

ABSTRACT

A resilient plastic drainage pipe of lightweight construction having spaced apart successively arranged annular ribs with interconnecting annular valley portions therebetween defining corrugations along the periphery of the pipe, the ribs being arranged in successive groups with each of the successive groups of ribs having at least several of the ribs interrupted by elongate recessed wall portions positioned at a level intermediate that of the peripheries of the ribs and the valley portions. The elongate recessed wall portions in each group of ribs are arcuately spaced from one another and positioned at three arcuately spaced locations in the lower half of the pipe with drainage holes provided in the elongate recessed wall portions, and with at least one of the elongate recesses in each group being offset longitudinally from an elongate recess in another rib in the group.

United States Patent Maroschak 11] 3,861,152 [451 Jan. 21, 1975CORRUGATED DRAINAGE PIPE WITH STAGGERED ARRANGEMENT OF PLATEAU RECESSES[76] Inventor: Ernest J. Maroschak, Box 878,

Roseboro, NC. 28382 [22] Filed: July 19, 1973 [21] Appl. No.: 380,904

Related U.S. Application Data [63] Continuation-in-part of Ser. No.262,103, June 12, 1972, Pat. No. 3,747,352, which is acontinuation-in-part of Ser. No. 228,508, Feb. 23, 1972, Pat. No.3,802,202.

[52] U.S. Cl 61/11, 6l/72.1,138/121, 138/173 [51] Int. Cl. E02b 11/00,F161 11/12 [58] Field of Search 61/11, 10, 12, 13, 72.1;138/105,121,173, 178

[56] References Cited UNITED STATES PATENTS 3,747,352 7/1973 Maroschak61/10 Primary ExaminerJacob Shapiro Attorney, Agent, or Firm-Parrott,Bell, Seltzer, Park & Gibson [57] ABSTRACT A resilient plastic drainagepipe of lightweight construction having spaced apart successivelyarranged annular ribs with interconnecting annular valley portionstherebetween defining corrugations along the periphery of the pipe, theribs being arranged in successive groups with each of the successivegroups of ribs having at least several of the ribs interrupted byelongate recessed wall portions positioned at a level intermediate thatof the peripheries of the ribs and the valley portions. The elongaterecessed wall portions in each group of ribs are arcuately spaced fromone another and positioned at three arcuately spaced locations in thelower half of the pipe with drainage holes provided in the elongaterecessed wall portions, and with at least one of the elongate recessesin each group being offset longitudinally from an elongate recess inanother rib in the group.

11 Claims, 7 Drawing Figures CORRUGATED DRAINAGE PIPE WITH STAGGEREDARRANGEMENT OF PLATEAU RECESSES This application is acontinuation-in-part of my copending application Ser. No 262,103, filedJune 12, 1972, entitled CORRUGATED DRAINAGE PIPE WITH PLATEAUS DEFININGRECESSES, now US. Pat. No. 3,747,352, which application, in turn, is acontinuation-in-part of my copending application Ser. No. 228,508, filedFeb. 23, 1972, entitled CORRUGATED DRAINAGE PIPE now U.S. Pat. No.3,802,202.

This invention relates to resilient plastic corrugated drainage pipe andit is an object of this invention to provide an improved drainage pipeof lightweight construction particularly adapted for use with septictanks.

In my earlier copending application Ser. No. 262,103, filed June 12,1972 a corrugated plastic drainage pipe is disclosed wherein a series ofthree arcuately spaced recessed wall portions or plateaus are providedin certain ribs of the pipe defining interruptions therein with theremaining ribs in the pipe being uninterrupted. A drainage hole isprovided in each of the recesses or plateaus in the interrupted ribs toallow liquids to drain from the pipe. The present invention differs overmy earlier copending application by providing the recessed wall portionsor plateaus in groups in arcuately spaced and longitudinally staggeredrelation so that at least one of the elongate recesses in each group islongitudinally spaced from other recesses in the same group.

The longitudinally staggered, arcuately spaced arrangement of therecesses or plateaus in accordance with the present invention providesseveral benefits over the arrangement disclosed in my earlier copendingapplication, as for example, facilitating drilling the drainage holes inthe pipe, since the drilling machines for forming the drainage holes inthe pipe may be staggered longitudinally from one another. Additionally,since the drainage holes are distributed along the length of the piperather than being grouped in a common rib, liquids may drain from thepipe uniformly along its length rather than from spaced locationstherealong as in my earlier application. Finally, the compressivestrength of the pipe is improved, since the drainage holes and theelongate recesses or interruptions in the ribs, which inherently formsomewhat weaker areas in the walls of the pipe than the uninterruptedportions thereof, are distributed more over the length of the piperather than being concentrated in selected ribs thereof.

In view of the foregoing, it is a more specific object of this inventionto provide an improved corrugated resilient plastic drainage pipe havingrecessed wall portions or plateaus provided in the ribs thereof instaggered relation along the length of the pipe.

Some of the objects and advantages of the invention having been stated,others will appear as the description proceeds when taken in connectionwith the accompanying drawings, in which FIG. 1 is a bottom plan view ofa length of corrugated drainage pipe in accordance with one form of thepresent invention, showing the drainage holes in the underside thereof;

FIG. 2 is a vertical sectional view of the drainage pipe taken along theline 2-2 of FIG. 1, and shown with the pipe in its normal orientationwith the drainage holes in the lower half thereof;

FIG. 3 is a vertical sectional view similar to FIG. 2 but taken alongthe line 3-3 of FIG. 1;

FIG. 4 is a bottom plan view of a length ofeorrugated drainage pipe inaccordance with a second form of this invention, showing the drainageholes in the underside thereof;

FIG. 5 is a vertical sectional view of the drainage pipe taken alongline 5-5 of FIG. 4 and shown with the pipe in its normal orientationwith the drainage holes in the lower half thereof;

FIG. 6 is a vertical sectional view similar to FIG. 5 but taken alongthe line 6-6 of FIG. 4; and

FIG. 7 is a vertical sectional view similar to FIG. 5 but taken alongline 77 of FIG. 4.

Referring now to the first form of the invention, as illustrated inFIGS. l-3, reference numeral 10 broadly indicates a corrugated drainagepipe in accordance with this invention which is formed ofa plasticmaterial such as polyethylene, with the wall thickness thereofpreferably being no greater than about l/l6 inch to provide a pipe oflightweight construction.

Successively arranged ribs 11 with interconnecting valley portions 12therebetween define annular corrugations along the periphery of thepipe, with the ribs 11 being somewhat wider than the valley portions 12and being provided with side wall portions Ila which connect with thevalley portions 12. As illustrated, the ribs are arranged in successivegroups of six ribs with two of the ribs in each group being interruptedby arcuately elongate recessed wall portions 20 and with the remain ingfour ribs in the group being uninterrupted and located in pairs betweensuccessive interrupted ribs.

It will be noted from FIG. 1 that two types of interrupted ribs areprovided, with alternate ones of the in terrupted ribs, broadlydesignated at 13, having a single recessed wall portion 20 therein andhaving an elongate arcuate rib segment 14 forming the remaining portionof the interrupted rib l3, and with the remaining interrupted ribs,designated at 15, having two arcuately spaced recessed wall portions 20therein with a relatively long arcuate rib segment 16 and a relativelyshort arcuate rib segment 17 interconnecting the two recessed wallportions and forming the remaining portions of the interrupted rib 15.

Each of the arcuately elongate recessed wall portions 20 are positionedradially outwardly from the axis of the pipe at a level intermediatethat of the peripheries of the ribs 11 and valley portions 12, with endwalls 21 at opposite ends of the recessed wall portions 20 extendingoutwardly and defining the arcuate extent of the interruptions in theinterrupted ribs and serving to provide compressive strength to theadjacent rib segments. As illustrated, recessed wall portions 20 have awidth corresponding to the medial portion of the adjacent arcuate ribsegments with side wall portions 20a extending radially inwardly towardthe axis of the pipe from opposite sides of the recessed wall portions20 and interconnecting the same with adjacent valley portions 12 andthereby serving to provide compressive strength to the recessed wallportions of the interrupted ribs. The recessed wall portions 20 may becharacterized as plateaus, since they are positioned outwardly from thevalley portions at a level intermediate the periphery of the valleyportions and the peripheries of the ribs.

As illustrated, the pipe is adapted for being used for drainagepurposes, as for example in a septic tank field,

and a drainage hole 23 is provided through each of the recessed wallportions 20 in the pipe to permit liquids to flow from the pipe.However, since corrugated plastic pipe is also conventionally used forvarious purposes without drainage holes therein, it may in someinstances be economically desirable to omit the drainage holes from therecessed wall portions 20 and to thereby employ the same moldingapparatus and mold blocks for forming solid or unperforated pipe as forforming drainage pipe having holes therein.

When the pipe is to be employed for drainage purposes, the holesprovided therein are of at least /2 inch diameter, and preferably aboutinch diameter so that the holes are of greater diameter than the widthof the recessed wall portions 20 and extend into the valley portionsadjacent opposite sides of the recessed wall portions 20. Thus, thedrainage holes will extend through two levels of the wall of the pipe,namely the recessed wall portions 20 on an intermediate level and thevalley portions 12 on a lower level, and will thereby effectivelyincrease the size of the drainage holes.

By locating the drainage holes in recessed portions of the pipe, thedrainage holes are spaced inwardly from the periphery of the ribs andaway from the surrounding soil when installed underground, whichfacilitates the drainage of liquids from the pipe.

Throughout the length of the pipe, the interrupted ribs 13, 15 in thesuccessive groups of ribs are correspondingly arranged so as to positionthe respective recessed wall portions or plateaus 20 in longitudinallyaligned rows at three arcuately spaced locations in the same half of thepipe. As seen in FIG. 1, the recessed wall portions 20 in successiveinterrupted ribs 13 are located at the middle or innermost location ofthe three arcuately spaced locations, with the two arcuately spacedrecessed wall portions 20 in succesive interrupted ribss 15 ribs locatedin longitudinally offset, arcuately spaced relation on opposite sidesthereof in the outermost of the three arcuately spaced locations.

When the drainage pipe is properly installed in the ground, the drainageholes 23 are located in the lower half of the pipe to permit drainage ofliquids therefrom into the earth below. For visually aiding ininstalling the pipe in the ground with the drainage holes properlyoriented lowermost, sight means 30 (FIGS. 2 and 3) is preferablyprovided longitudinally of the pipe in diametrically opposed relation tothe drainage hole in interrupted rib 13, which as previously noted, isin the middle or innermost of the three arcuately spaced locations. Asillustrated, sight means 30 is in the form of a painted line contrastingwith the color of the drainage pipe, but may, if desired, be in the formof a series of small rib portions extending longitudinally of the pipealong the outer surface of the ribs.

Referring more particularly to interrupted rib 15, rib segment 16thereof, as noted earlier, is of greater arcuate extent than the otherrib segment 17. Rib segment 16 desirably has an arcuate extentencompassing at least the upper half of the drainage pipe, i.e., atleast 180 degrees, and preferably has an extent of at least 200 to 220degrees so as to shieldingly protect the two drainage holes 23 duringthe backfilling of earth around the drainage pipe to avoid blocking theholes. As illustrated (FIG. 2), the intersecting axes of the arcuatelyspaced holes in interrupted rib l define an included angle of about 120degrees (angle A), with each drainage hole also being arcuately spacedabout 120 degrees from the top of the pipe where sight means 30 islocated.

Each elongate recessed wall portion preferably has an arcuate extent ofabout 3550 degrees to provide sufficient room for drilling drainageholes 23 therein, which as illustrated, encompass an arcuate extent ofabout 15 to 25 degrees and are preferably centered in the elongaterecessed wall portions. The additional arcuate extent of the elongaterecessed wall portions serves to provide a degree of tolerance for minormisalignment of the pipe with respect to the drilling apparatus duringthe drilling operation.

Referring to interrupted rib 13, it will be noted that the recessed wallportion 20 thereof has an arcuate extent similar to that of the recessesin interrupted rib 15, with arcuate rib segment 14 comprising theremaining portion of the interrupted rib. As illustrated. drainage hole23 in rib 15 is located lowermost in the pipe about 180 degrees from thetop of the pipe where sight means 30 is located. Thus, as illustrated inFIG. 1, the drainage holes in the pipe collectively cover an arcuateextent of about degrees in the lower portion of the pipe and form threelongitudinally aligned rows of drainage holes, which rows are arcuatelyspaced about 60 degrees apart from each other.

The second form of the invention, as illustrated in FIGS. 47, is similarto the first form illustrated in FIGS. 13, and the same referencenumerals have been employed for like elements where applicable, exceptthat the three interrupted ribs in each group of six ribs are identifiedby the reference numerals 40, 42 and 44 respectively.

Referring to FIG. 4, it will be noted that the ribs 11 are arranged insuccessive groups of six ribs with three of the ribs in each group (40,42, 44) being interrupted by a recessed wall portion 20, and with theremaining three ribs in each group being uninterrupted and locatedbetween successive interrupted ribs. The recessed wall portion in eachof the interrupted ribs 40, 42, 44 has an arcuate extent of about 3550degrees, with elongate arcuate rib segments 41, 43, 45 respectively,comprising the remaining portions of the respective interrupted ribs.

As in the first form of the invention, the interrupted ribs (40, 42, 44)are correspondingly arranged throughout the length of the pipe so as toposition the respective recessed wall portions or plateaus in threelongitudinally aligned rows at three arcuately spaced locations in thesame half of the pipe. The recessed wall portion in interrupted rib 42is located at the middle or innermost location of the three arcuatelocations, with the recessed wall portion in interrupted rib 40 beinglocated on one side thereof, and with the recessed wall portions ininterrupted rib 44 being located on the opposite side thereof. Sightmeans 30 is also preferably provided in diametrically opposed relationto the drainage holes in interrupted rib 42 for visually aiding ininstalling the pipe in the ground with the drainage holes properlypositioned lowermost.

As illustrated, the drainage hole in interrupted rib 40 is located inthe recessed wall portion 20 on one side of the pipe and arcuatelyspaced about 120 degrees from the top of the pipe where sight means 30is located (angle B in FIG. 5), while the drainage hole in interruptedrib 44 is located in the recessed wall portion 20 on the opposite sideof the pipe and also spaced about 120 degrees from the top of the pipe(angle C in FIG. 7). As previously noted, the drainage hole ininterrupted rib 42 is positioned in diametrically opposed relation tosight means 30 at the top of the pipe.

Thus, as seen in FIG. 4, the drainage holes collectively cover anarcuate extent of about 120 degrees in the lower portion of the pipe andform three longitudinally aligned rows of holes which are arcuatelyspaced about 60 degrees apart from each other.

It will be noted that in both of the illustrated forms of thisinvention, at least one of the drainage holes in each group of ribs isin longitudinally offset or staggered relation with respect to anotherdrainage hole in the group with no two drainage holes being positionedclosely adjacent one another in the same rib. Thus, the inherentweaknesses in the wall of the pipe formed by the drainage holes and therecessed wall portions are distributed throughout the length of the piperather than being concentrated in a single rib as in my aforementionedearlier-filed copending application. It should be apparent from theforegoing that the instant invention thus provides a corrugated plasticdrainage pipe of enhanced compressive strength as compared to my earlierinvention disclosed in the aforementioned copending application.

In the drawings and specification there have been set forth preferredembodiments of the invention, and although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation.

That which is claimed is:

l. A resilient plastic pipe having spaced apart successive annular ribswith annular valley portions therebetween defining corrugations alongthe periphery of the pipe, said ribs being arranged in successive groupswith each of the successive groups of ribs having at least several ribsin the group interrupted by elongate recessed wall portions positionedat a level intermediate that of the peripheries of said ribs and saidvalley portions, and wherein the respective elongate recessed wallportions in each group of ribs are arcuately spaced from one anotherwith at least one of the elongate recessed wall portions being offsetlongitudinally of the pipe from an elongate recessed wall portion inanother rib of the group.

2. A resilient plastic pipe according to claim 1, wherein drainage holesare provided in the elongate recessed wall portions in each group ofribs with the diameter of the holes being greater than the width of theribs.

3. A resilient plastic pipe according to claim 1, wherein side wallsextend radially inwardly from opposite sides of said elongate recessedwall portions and interconnect the same with said valley portions.

4. A resilient plastic pipe according to claim 1 wherein at least oneuninterrupted rib is positioned between adjacent interrupted ribsthroughout the pipe.

5. A resilient plastic pipe according to claim 1, wherein the respectiveelongate recessed wall portions in each group of ribs are each offsetlongitudinally of the pipe from one another.

6. A resilient plastic pipe according to claim I wherein two of theelongate recessed wall portions in each group of ribs are located in acommon interrupted rib and wherein the remaining elongate recessed wallportion in each group of ribs are offset longitudinally of the pipe fromsaid common interrupted rib.

7. A resilient plastic pipe having spaced apart successive annular ribswith annular valley portions therebetween defining corrugations alongthe periphery of the pipe, said ribs being arranged in successive groupswith each of the successive groups of ribs having at least sev eral ribsin the group interrupted by arcuately elongate recessed wall portionspositioned at a level intermediate that of the peripheries of said ribsand said valley portions, the elongate recessed wall portions in eachgroup of ribs being three in number and being arcuately spaced apartfrom each other at three arcuate locations in the lower half of thepipe, and with the elongate rccessed wall portions in adjacent groups ofribs being positioned in similar arcuate locations, and wherein at leastone of the elongate recessed wall portions ineach group of ribs isoffset longitudinally of the pipe from an elongate recessed wall portionin another rib of the group.

8. A resilient plastic pipe according to claim 7, wherein a drainagehole is provided in each of the three arcuately spaced recessed wallportions in each group of ribs with the diameter of the holes beinggreater'than the width of the ribs.

9. A resilient plastic pipe according to claim 8, wherein the drainageholes in each group of ribs are arcuately spaced from each other about60 degrees apart, and wherein sight means is provided on the outersurface of said pipe extending longitudinally thereof and located indiametrically opposed relation to the middle location of the arcuatelyspaced drainage holes in the pipe, said sight means being therebyadapted for visually aiding in installing the pipe in the ground withall of the drainage holes located below the horizontal center line ofthe pipe and with the middle drainage holes occupying the lowermostposition.

10. A resilient plastic pipe according to claim 7, wherein each group ofribs includes three interrupted ribs with an uninterrupted rib beingprovided between adjacent interrupted ribs, and wherein each of thethree interrupted ribs has one of said elongate recessed wall portionsprovided therein with said recessed wall portions being locatedrespectively at said three different arcuate locations on the pipe.

11. A resilient plastic pipe according to claim 7, wherein each group ofribs includes two longitudinally spaced interrupted ribs with a pair ofuninterrupted ribs being provided therebetween, and wherein two of theelongate recessed wall portions in each group of ribs are positioned ina common interrupted rib in arcuately spaced relation in the outermostof said three arcuate locations, with the third elongate recessed wallportion being positioned in the other interrupted rib and located in themiddle of said three arcuate locations.

1. A resilient plastic pipe having spaced apart successive annular ribs with annular valley portions therebetween defining corrugations along the periphery of the pipe, said ribs being arranged in successive groups with each of the successive groups of ribs having at least several ribs in the group interrupted by elongate recessed wall portions positioned at a level intermediate that of the peripheries of said ribs and said valley portions, and wherein the respective elongate recessed wall portions in each group of ribs are arcuately spaced from one another with at least one of the elongate recessed wall portions being offset longitudinally of the pipe from an elongate recessed wall portion in another rib of the group.
 2. A resilient plastic pipe according to claim 1, wherein drainage holes are provided in the elongate recessed wall portions in each group of ribs with the diameter of the holes being greater than the width of the ribs.
 3. A resilient plastic pipe according to claim 1, wherein side walls extend radially inwardly from opposite sides of said elongate recessed wall portions and interconnect the same with said valley portions.
 4. A resilient plastic pipe according to claim 1 wherein at least one uninterrupted rib is positioned between adjacent interrupted ribs throughout the pipe.
 5. A resilient plastic pipe according to claim 1, wherein the respective elongate recessed wall portions in each group of ribs are each offset longitudinally of the pipe from one another.
 6. A resilient plastic pipe according to claim 1 wherein two of the elongate recessed wall portions in each group of ribs are located in a common interrupted rib and wherein the remaining elongate recessed wall portion in each group of ribs are offset longitudinally of the pipe from said common interrupted rib.
 7. A resilient plastic pipe having spaced apart successive annular ribs with annular valley portions therebetween defining corrugations along the periphery of the pipe, said ribs being arranged in successive groups with each of the successive groups of ribs having at least several ribs in the group interrupted by arcuately elongate recessed wall portions positioned at a level intermediate that of the peripheries of said ribs and said valley portions, the elongate recessed wall portions in each group of ribs being three in number and being arcuately spaced apart from each other at three arcuate locations in the lower half of the pipe, and with the elongate recessed wall portions in adjacent groups of ribs being positioned in similar arcuate locations, and wherein at least one of the elongate recessed wall portions in each group of ribs is offset longitudinally of the pipe from an elongate recessed wall portion in another rib of the group.
 8. A resilient plastic pipe according to claim 7, wherein a drainage hole is provided in each of the three arcuately spaced recessed wall portions in each group of ribs with the diameter of the holes being greater than the width of the ribs.
 9. A resilient plastic pipe according to claim 8, wHerein the drainage holes in each group of ribs are arcuately spaced from each other about 60 degrees apart, and wherein sight means is provided on the outer surface of said pipe extending longitudinally thereof and located in diametrically opposed relation to the middle location of the arcuately spaced drainage holes in the pipe, said sight means being thereby adapted for visually aiding in installing the pipe in the ground with all of the drainage holes located below the horizontal center line of the pipe and with the middle drainage holes occupying the lowermost position.
 10. A resilient plastic pipe according to claim 7, wherein each group of ribs includes three interrupted ribs with an uninterrupted rib being provided between adjacent interrupted ribs, and wherein each of the three interrupted ribs has one of said elongate recessed wall portions provided therein with said recessed wall portions being located respectively at said three different arcuate locations on the pipe.
 11. A resilient plastic pipe according to claim 7, wherein each group of ribs includes two longitudinally spaced interrupted ribs with a pair of uninterrupted ribs being provided therebetween, and wherein two of the elongate recessed wall portions in each group of ribs are positioned in a common interrupted rib in arcuately spaced relation in the outermost of said three arcuate locations, with the third elongate recessed wall portion being positioned in the other interrupted rib and located in the middle of said three arcuate locations. 